Two more inmates and six correctional deputies have tested positive for covid-19, according to the San Luis Obispo County Sheriff's Office.
The jail outbreak started Dec. 10.
California's Department of Public Health defines an outbreak as three or more cases that are linked.
Infected inmates and deputies have been isolated, and the affected housing units have been quarantined.
Officials with the sheriff's office say they are working with the San Luis Obispo County Public Health Department to contain the spread of covid-19 and investigate the source of the outbreak.
A total of 17 inmates and 20 sheriff's deputies have tested positive, as well as eight patrol deputies and 12 correctional deputies.